The desertc4.zip file you have requested: Skins / C4 / CS: Source Desert C4 Skin - 733.11kb is not available. Perhaps try browsing all files for the game Counter-Strike: Source and upload any files you want to share or are missing. This is the only information we could locate:
This skin changes the look of the current C4 to that of a more "desert" look. To do that, basically the main body of the C4 has been changed to a tan color to help better blend in with desert enviroments.